Ciphers (lock and key system, with sliding paper strips attached) and explanations; also a table for computing compound interest at 6 per cent a year, payable quarterly
7 p. (in JQA's hand) in a series numbered in pencil 1–18 (the date "7. Decr. 1809.f." appears on p. 12 only). (Note that p. 19–21 are a different size of sheet and may not belong with this batch at all.)
Watermarks: "E Patterson W City 1806" except on p. 2–5, which is a different paper and probably indicates that the table for computing interest (written thereon) does not actually belong with the cipher material.